1. Field of the Invention
The present invention relates to a pipe connector having a tubular body for carrying a fluid and a valve mechanism placed in the tubular body and, more particularly, to a pipe connector provided with a valve cartridge.
2. Description of the Related Art
Some pipe connectors are provided with a built-in valve mechanism. A pipe connector disclosed in JP-A 2002-168385 or JP-A 2003-028010 has a connector body and a valve mechanism built into the connector body. In this pipe connector, a valve seat having a valve opening is formed inside the connector body. A valve element is seated on the valve seat and a compression coil spring presses the valve element against the valve seat.
When the pressure of a fluid flowing through this pipe connector provided with the built-in valve mechanism increases, the fluid separates the valve element from the valve seat against the resilience of the compression coil spring to open the valve opening. The flow rate of the fluid flowing through the pipe connector is dependent on the spring characteristic of the compression coil spring. Therefore, this valve mechanism fails in the stable control of the flow rate when the spring characteristic changes with time.
A pipe connector provided with a built-in valve mechanism proposed in JP-A 2005-163836 to solve the foregoing problem is provided with a flow regulating orifice in addition to a valve opening opened and closed by a valve element pressed by a compression coil spring. The flow regulating orifice removes the influence of the characteristic of the compression coil spring on flow rate.
The valve mechanism built into the known pipe connector includes the valve seat formed in the connector body, and the valve element as essential elements. Therefore, the shape of the connector body necessarily needs to be changed to change the functional characteristics of the valve mechanism. Thus, the functional characteristics of the valve mechanism cannot be easily changed.
When the shape of the connector body is changed, the surface of the valve seat, the valve element and the compression coil spring need to be adjusted carefully and ascertained such that the valve element is lifted up by a predetermined pressure and a predetermined flow rate can be stably maintained.
Therefore, the functional valve parts need to be examined in combination with the connector body. Thus, the manufacture of pipe connectors provided with a valve mechanism for different uses and having different characteristics requires much time and labor, which increases the cost of the pipe connectors.